Patent GB-985017-A (GB)
Title: Automatic heating control system
IPC: G05D23/275
Filed: 1963-11-29
Abstract: 985,017. Automatic temperature control. WERKSPOOR N.V. Nov. 29, 1963 [Nov.30, 1962], No. 47214/63. Heading G3R. An automatic temperature control system for a room comprises an oil burner 1 supplied through a valve 2, the air supporting combustion being supplied by a blower motor 4,the heat vehicle-either air or water-being circulated over the burner space from an inlet 8 to an outlet 9 by a motor 7 (62 in Fig. 3) a number of serially connected thermostats 13 being disposed in the circulation system and a thermostat 51 (see Fig. 3) being arranged to control the fuel supply and the speed of the motors 4, 7 to control the room temperature. When the temperature of the heat vehicles is low the contacts I, II, III,IV of thermostats 13 (see Fig. 3) together with those of thermostat 51 are closed whilst those of a minimum temperature thermostat 67 are open. According to weather conditions one of the push buttons 60 is operated (the centre one for example) to close its associated contacts 48, 61. Switch 44 is closed and the burner 1 ignited,the fuel valve 2 and the speed of the blower motor 4 adjusted to provide a desired burner operation. At this point a switch 54 is in contact with the contact 55. With the closure of switch 44, relays 64, 65 pick up to connect the circulating motor 62 to the lowest tap on an autotransformer 59. When now the temperature of the heat vehicle around the burner 1 reaches a desired minimum temperature, the contacts of thermostat 67 close whereupon the circulation motor 62 is energized to run at minimum speed to circulate the heat vehicle slowly. As the temperature of the heat vehicle rises the contacts of thermostat I open first with no operational effect. Further increase in the temperature of the heat vehicle causes opening of the contacts of thermostat II so de-energizing relay 64 whereupon the circulation motor 62 is connected to a higher voltage tapping on the autotransformer 59 causing it to run at a higher speed and hence causing faster circulation of the heat vehicle. Still further increase in the temperature of the heat vehicle causes opening of the contacts of thermostat III whereupon the supply to a transformer 46 energizing the heater 52 of a bimetal element 53 controlling the fuel valve 2 is removed. The bimetal element thus cools down to cause throttling of the valve 2 and also causing a switch 54 to change over to contact 57 whereupon the blower motor is connected to the lowest voltage tapping on the autotransformer 59 and hence runs at a reduced speed. When the heat vehicle cools down the contacts of thermostat III reclose to re-energize the transformer 46 thus controlling the temperature of the room at a value selected by the appropriate push button 60. If the room becomes too warm the room thermostat 51 opens to cause throttling of the fuel valve 2 and slow running of the blower motor 4. Should cooling be required the lowest push button 60 is operated, the burner 1 remaining unlit in this case. Operation of this push buttom permanently de-energizes relay 64 and short circuits the contacts 67 of the minimum temperature thermostat, the speed of the circulation motor 62 then being selected by operation of one of the remaining push buttons 60. The system may be made completely automatic by causing the operation of the push buttons 60 to be made responsive to a heatable thermally conductive strip (Fig. 4 not shown).